Rear derailleur – Shimano RD-M3020 Acera

22,40 
7-8 speed, long cage, max 40T, capacity 45T

Rear derailleur – microSHIFT Advent RD-M6195S

36,11 
1x9 speed. Max cog 34-38T, capacity 27T. Super Short cage is an ideal fit for kids bikes with 20" wheels. With adjustable clutch for increased chain tension. Compatible with microSHIFT Advent MTB (SL-M9195, SL-9295, SL-8195, SL-819) gear shifters and Road (SB-M090) shift brake levers.